Development of the Oriental Latrine Fly, Chrysomya megacephala (Diptera: Calliphoridae), at Five Constant Temperatures.
J Med Entomol. 2017 Mar 01;54(2):290-298
Authors: Gruner SV, Slone DH, Capinera JL, Turco MP
Chrysomya megacephala (Fabricius) is a forensically important fly that is found throughout the tropics and subtropics. We calculated the accumulated development time and transition points for each life stage from eclosion to adult emergence at five constant temperatures: 15, 20, 25, 30, and 35 °C. For each transition, the 10th, 50th, and 90th percentiles were calculated with a logistic linear model. The mean transition times and % survivorship were determined directly from the raw laboratory data. Development times of C. megacephala were compared with that of two other closely related species, Chrysomya rufifacies (Macquart) and Phormia regina (Meigen). Ambient and larval mass temperatures were collected from field studies conducted from 2001-2004. Field study data indicated that adult fly activity was reduced at lower ambient temperatures, but once a larval mass was established, heat generation occurred. These development times and durations can be used for estimation of a postmortem interval (PMI).
PMID: 27816915 [PubMed – indexed for MEDLINE]
Development of the Forensically Important Beetle Creophilus maxillosus (Coleoptera: Staphylinidae) at Constant Temperatures.
J Med Entomol. 2017 Mar 01;54(2):281-289
Authors: Wang Y, Yang JB, Wang JF, Li LL, Wang M, Yang LJ, Tao LY, Chu J, Hou YD
Creophilus maxillosus (L., 1758) is a common and widely distributed beetle species found on corpses, and its development duration is far longer than species belonging to the genus Calliphoridae and Sarcophagidae. Therefore, C. maxillosus can be used as a supplementary indicator to estimate minimum postmortem interval (PMImin), and could greatly extend the range of PMImin when the primary colonizers are no longer associated with the corpse or have emerged from pupae. Better descriptions of C. maxillosus development are needed to apply this species for forensic investigations. In this study, the development of C. maxillosus at seven constant temperatures ranging from 17.5-32.5 °C was studied. Through regression analyses, the simulation equations of larval body length variation with time after hatching were obtained. Isomegalen diagrams of the changes of larval body length over time at specific temperatures, and the isomorphen diagrams on the duration of different developmental milestones at specific temperatures were generated. In addition, thermal summation models of different developmental stages and the overall development process of C. maxillosus were generated through regression analysis, by estimating the development threshold temperatures (D0) and the thermal summation constants (K). These results provide important tools for forensic investigations to generate a long-range of PMImin estimation based on the development of C. maxillosus.
PMID: 28011726 [PubMed – indexed for MEDLINE]
DNA-Based Identification of Forensically Important Blow Flies (Diptera: Calliphoridae) From India.
J Med Entomol. 2017 Apr 17;:
Authors: Bharti M, Singh B
Correct species identification is the first and the most important criteria in entomological evidence-based postmortem interval (PMI) estimation. Although morphological keys are available for species identification of adult blow flies, keys for immature stages are either lacking or are incomplete. In this study, cytochrome oxidase subunit 1 (COI) reference data were developed from nine species (belonging to three subfamilies, namely, Calliphorinae, Luciliinae, and Chrysomyinae) of blow flies from India. Seven of the nine species included in this study were found suitable for DNA-based identification using COI gene, because they showed nonoverlapping intra- (0.0-0.3%) and inter-(1.96-18.14%) specific diversity, and formed well-supported monophyletic clade in phylogenetic analysis. The remaining two species (i.e., Chrysomya megacephala (Fabricius) and Chrysomya chani Kurahashi) cannot be distinguished reliably using our database because they had a very low interspecific diversity (0.11%), and Ch. megacephala was paraphyletic with respect to Ch. chani in the phylogenetic analysis. We conclude that the COI gene is a useful marker for DNA-based identification of blow flies from India.
PMID: 28419283 [PubMed – as supplied by publisher]
Effect of Continuous and Cyclic Exposure to a Cold Environment on the Development of Larvae of Lucilia sericata (Diptera: Calliphoridae) in Different Sized Larval Masses.
J Med Entomol. 2016 Apr 25;
Authors: Magni PA, Dhaliwal SS, Dadour IR
Regulation of forensic practice in many countries prevents the pathologist performing an immediate autopsy. During the period prior to autopsy, the corpse and the insects possibly associated with it are stored in a mortuary with temperatures ∼4°C. When a corpse is found in a late stage of decay, fly immatures may be present as small or large larval masses. The purpose of refrigeration at 4°C is to slow down the decomposition of the corpse as well as the temporary disruption of the activity and development of the bacteria and the necrophagous insects associated with the corpse. The aim of this research is to investigate the growth and development of different larval masses of the blowfly Lucilia sericata (Meigen) (Diptera: Calliphoridae) when stored in a cold environment (4°C). The research was divided into experimental sessions comprising different storage conditions (continuous or cyclic exposure to a cold environment) for immature stages (second and third instar) and included four different sizes of larval mass (∼100, 500, 1,000, and 5,000 larvae) feeding on 4 kg of beef liver and replicated three times. Results show that if the larval mass has a size of ∼5,000 larvae, and the larvae have already reached third instar, then when they are exposed to a cold environment, their development continues. The storage condition at 4°C does not disrupt the development of such larvae. The number of larvae and their instar that make up the larval mass are essential data for the subsequent estimation of a correct minimum postmortem interval.
PMID: 27113109 [PubMed – as supplied by publisher]
Dynamics of Necrophagous Insect and Tissue Bacteria for Postmortem Interval Estimation During the Warm Season in Romania.
J Med Entomol. 2016 Jan;53(1):54-66
Authors: Iancu L, Sahlean T, Purcarea C
The estimation of postmortem interval (PMI) is affected by several factors including the cause of death, the place where the body lay after death, and the weather conditions during decomposition. Given the climatic differences among biogeographic locations, the understanding of necrophagous insect species biology and ecology is required when estimating PMI. The current experimental model was developed in Romania during the warm season in an outdoor location. The aim of the study was to identify the necrophagous insect species diversity and dynamics, and to detect the bacterial species present during decomposition in order to determine if their presence or incidence timing could be useful to estimate PMI. The decomposition process of domestic swine carcasses was monitored throughout a 14-wk period (10 July-10 October 2013), along with a daily record of meteorological parameters. The chronological succession of necrophagous entomofauna comprised nine Diptera species, with the dominant presence of Chrysomya albiceps (Wiedemann 1819) (Calliphoridae), while only two Coleoptera species were identified, Dermestes undulatus (L. 1758) and Creophilus maxillosus Brahm 1970. The bacterial diversity and dynamics from the mouth and rectum tissues, and third-instar dipteran larvae were identified using denaturing gradient gel electrophoresis analysis and sequencing of bacterial 16S rRNA gene fragments. Throughout the decomposition process, two main bacterial chronological groups were differentiated, represented by Firmicutes and Gammaproteobacteria. Twenty-six taxa from the rectal cavity and 22 from the mouth cavity were identified, with the dominant phylum in both these cavities corresponding to Firmicutes. The present data strengthen the postmortem entomological and microbial information for the warm season in this temperate-continental area, as well as the role of microbes in carcass decomposition.
PMID: 26487246 [PubMed – indexed for MEDLINE]
A Biological and Procedural Review of Forensically Significant Dermestes Species (Coleoptera: Dermestidae).
J Med Entomol. 2015 Jul 25;
Authors: Magni PA, Voss SC, Testi R, Borrini M, Dadour IR
The analyses of the insect species found on decomposing remains may provide useful information for the estimation of the minimum time elapsed since death and other parameters, such as causes and circumstances of death. The majority of research has focused on the early colonizing species, typically blowflies, while research concerning late colonizing insects is currently sparse. Dermestid beetles of the genus Dermestes L. (Coleoptera: Dermestidae) are one of the predominant insect species associated with decomposing remains during dry decay and skeletal stages of decomposition. In some dry environments, Dermestes species are likely to be the only necrophagous insects feeding on the decomposing remains. Furthermore, Dermestes species (immature and adults), their remains (cast skins and fecal material), and their artifacts (pupal chambers) are frequently found associated with ancient remains (e.g., mummies, fossils). Dermestes species have a worldwide distribution and are considered important in decomposition processes, forensic investigations, and economically as a known pest of stored products. Despite their recognized forensic importance, there is limited data documenting the ecology, biology, and the growth rates of the forensically relevant species. The aim of this review is to provide a comprehensive synopsis on the available literature concerning Dermestes species associated with forensic cases. In particular, aspects of colonization behavior, growth rates for forensic taxa and potential best practice guidelines for forensic casework encompassing late colonizing Dermestes species are discussed.
PMID: 26336246 [PubMed – as supplied by publisher]
Human wound colonization by Lucilia eximia and Chrysomya rufifacies (Diptera: Calliphoridae): myiasis, perimortem, or postmortem colonization?
J Med Entomol. 2014 May;51(3):716-9
Authors: Sanford MR, Whitworth TL, Phatak DR
The infestation of human or animal tissues by fly larvae has been given distinctive terminology depending on the timing and location of colonization. Wounds and orifices colonized by Diptera in a living human or animal are typically referred to as myiasis. When the colonization occurs after death, it is referred to as postmortem colonization and can be used to estimate the minimum postmortem interval. What happens when the human, as in the case presented here, has a necrotic limb while the human remains alive, at least for a short period of time? The case presented here documents perimortem wound colonization by Lucilia eximia (Wiedemann) and Chrysomya rufifacies (Macquart) and the considerations for approximating development temperatures and estimating the time of colonization (TOC). This represents the first record of L. eximia in human myiasis in the United States and the first record of the co-occurrence of L. eximia and C. rufifacies in human myiasis in the United States. The TOC was estimated using both ambient and body temperature. Insect colonization before death complicates the estimation of TOC and minimum postmortem interval and illustrates the problem of temperature approximation in forensic entomology casework.
PMID: 24897868 [PubMed – indexed for MEDLINE]
Environmental factors affecting early carcass attendance by four species of blow flies (Diptera: Calliphoridae) in Texas.
J Med Entomol. 2014 May;51(3):702-8
Authors: Mohr RM, Tomberlin JK
As the most common primary colonizer of carrion, adult blow flies (Diptera: Calliphoridae) play an important role in initiating arthropod-mediated breakdown of soft tissue; however, their timing is highly variable. This variability complicates the estimation of precolonization intervals or periods of insect activity by forensic entomologists. In this study, the size of the adult blow fly on swine carcasses was compared with various environmental conditions including time of day, temperature, wind speed, and light levels. Four trials were conducted: two in August and September 2008, one in January 2009, and one in February-March 2010. Of the measured variables, time of day was the only consistent factor explaining the population size of blow fly on a carcass, although precipitation and high winds affected winter-active Calliphora vicina Robineau-Desvoidy. Male flies were also collected, suggesting that carcasses may play additional roles in adult blow fly ecology beyond that of a simple oviposition site. For both sexes of flies, a strong diel pattern of behavior emerged, which could be useful in estimating precolonization intervals by considering the environmental conditions at a scene, and thus forensic entomologists may be better able to estimate the likelihood of adult activity at a carcass.
PMID: 24897865 [PubMed – indexed for MEDLINE]
Forensic entomology investigations from Doctor Marcel Leclercq (1924-2008): a review of cases from 1969 to 2005.
J Med Entomol. 2013 Sep;50(5):935-54
Authors: Dekeirsschieter J, Frederickx C, Verheggen FJ, Boxho P, Haubruge E
Dr. Marcel Leclercq was a pioneer in the field of forensic entomology. He has provided his knowledge of insect biology to many forensic cases, and most of them have found the way to publication. Most of the articles he has written were focused on individual cases, and despite the abundance of entomoforensic investigations he conducted, no synthesis has been published. This article summarizes 36 yr of forensic entomological investigations in temperate Europe, mainly in Belgium. Dr. Leclercq’s work includes 132 entomological cases involving 141 human corpses found in various death scenes. Under certain conditions, insect specimens found at death scene can provide information on when (postmortem interval estimation), where and how a person died. More or less 100 insect species associated with a dead body have been identified by Dr. Leclercq.
PMID: 24180097 [PubMed – indexed for MEDLINE]
Oviposition preferences of two forensically important blow fly species, Chrysomya megacephala and C. rufifacies (Diptera: Calliphoridae), and implications for postmortem interval estimation.
J Med Entomol. 2012 Mar;49(2):424-35
Authors: Yang ST, Shiao SF
Necrophagous blow fly species (Diptera: Calliphoridae) are the most important agents for estimating the postmortem interval (PMI) in forensic entomology. Nevertheless, the oviposition preferences of blow flies may cause a bias of PMI estimations because of a delay or acceleration of egg laying. Chrysomya megacephala (F.) and C. rufifacies (Macquart) are two predominant necrophagous blow fly species in Taiwan. Their larvae undergo rather intense competition, and the latter one can prey on the former under natural conditions. To understand the oviposition preferences of these two species, a dual-choice device was used to test the choice of oviposition sites by females. Results showed when pork liver with and without larvae of C. rufifacies was provided, C. megacephala preferred to lay eggs on the liver without larvae. However, C. megacephala showed no preference when pork liver with and without conspecific larvae or larvae of Hemipyrellia ligurriens (Wiedemann) was provided. These results indicate that females of C. megacephala try to avoid laying eggs around larvae of facultatively predaceous species of C. rufifacies. However, C. rufifacies showed significant oviposition preference for pork liver with larvae of C. megacephala or conspecific ones when compared with pork liver with no larvae. These results probably imply that conspecific larvae or larvae of C. megacephala may potentially be alternative food resources for C. rufifacies, so that its females prefer to lay eggs in their presence. When considering the size of the oviposition media, pork livers of a relatively small size were obviously unfavorable to both species. This may be because females need to find sufficient resources to meet the food demands of their larvae. In another experiment, neither blow fly species showed an oviposition preference for pork livers of different stages of decay. In addition, the oviposition preferences of both species to those media with larvae were greatly disturbed in a dark environment. If we removed the larvae that had previously fed on the pork liver and let the females choose, no oviposition preference was observed; but both species still showed a preference for the larger media in the dark. This suggests that female blow flies can use visual cues to recognize larvae on the media and decide on their oviposition site. Our studies point out the effects of some biotic and abiotic factors which were previously overlooked, and remind us to reevaluate these effects on oviposition, especially when using insect developmental data to estimate PMIs.
PMID: 22493863 [PubMed – indexed for MEDLINE]